Updated

MIAMI -- State authorities said Thursday they are investigating financial dealings by South Florida U.S. Rep. David Rivera, who failed to report loans from his mother's gambling-related marketing company before the election.

Florida Department of Law Enforcement Spokesman Keith Kameg said his agency is leading the investigation involving the freshman Republican congressman. Kameg said the department received a complaint from the State Attorney's Office in October related to Rivera and opened an investigation into the then-candidate. He declined to provide details or say when his agency took over the probe.

"We'll be working in partnership with the Miami-Dade County Police Department and the State Attorney's Office," he said. "This is an active investigation, so we won't be discussing any facets of it."

Kameg said the investigation is being conducted by the agency's public integrity division in Tallahassee.

Cmdr. Nancy Perez, spokeswoman for the Miami-Dade Police Department, confirmed her agency's Public Corruption Bureau is investigating Rivera's finances. She declined to say if the loans were the issue or just what was under investigation. The Miami-Dade State Attorney's Office did not immediately respond to phone and e-mail requests for comment.

So far the investigation appears to be limited to state agencies, although there could be some aspects of the case that involve federal law. Alicia Valle, a spokeswoman for the Miami U.S. Attorney's Office, would not confirm or deny the existence of a federal investigation. The Federal Election Commission also confirmed Thursday it is reviewing a complaint filed last fall by a supporter of Rivera's opponent over campaign finance violations.

Asked if he had been contacted by authorities, Rivera provided an e-mail from his campaign address stating: "Mr. Rivera will not be commenting on any matters related to legal representation or investigators."

Rivera has been criticized for not disclosing before the November election that he ran a campaign to persuade Miami-Dade County voters to approve slot machines. Voters rejected slots in 2005 but approved them three years later, following the campaign led by Rivera.

Rivera says he didn't have to list his work on his financial disclosure forms because he was not paid anything. The slots campaign was arranged through a $500,000 contract with a company called Millennium Marketing Strategies -- which was co-managed by Rivera's mother and a close family friend out of their small Miami condo. The contract makes clear Rivera was the point man for anyone hired to work on the campaign.

Millennium provided Rivera $132,000 in loans, which he did not report until he amended his congressional financial disclosure forms weeks after winning election. He also reported that he had repaid the loans with interest.

Rivera says he sold stocks and property to repay the loan, but details remain unclear.

Rivera said in the federal disclosures filed earlier this month that he sold more than $100,000 in real estate on Nov. 10, 2010. But Miami-Dade County property records show only that he transferred one of his three properties to his mother's company for what appeared to be $100, based on the county taxes he paid for the transactions.

His mother, and family friend, Ilena Medina, who co-managed Millenium, are listed as the witnesses to the transaction. Medina is listed as the notary public. Florida law bars notary publics from officiating any transactions for which they have a financial interest.

Following a story by The Miami Herald on the sale, the records were later amended to add more than $600 in county taxes, meaning the house was sold for $100,000.

Rivera blamed the change on a clerical error.

The amendment to his property sale is the latest in a series of changes Rivera has made to his financial statements over the last year following or in advance of media reports on his finances. During the campaign, he deleted eight years' worth of references to work he provided for the U.S. Agency for International Development and has yet to explain why he repeatedly claimed to have done work for the agency.

Rivera's latest filing showed he made just under $30,000 annually in his previous job as a four-term state lawmaker from South Florida.